1. Field of the Invention
The present invention relates to an information processing apparatus and method, and to a recording medium. More particularly, the present invention relates to an information processing apparatus and method in which, when two MPEG streams are connected, the audio data playback timing is shifted so that the audio data can be played back continuously so that continuous audio data can be played back at the point where the two MPEG streams are connected, and to a recording medium.
2. Description of the Related Art
In a case where audio data is compressed, the audio data is divided in predetermined units, and compression is performed within the divided data. When the audio data compressed in this manner is edited and connected, connection is possible only in divided data units (that is, connection is not possible from the middle of data units).
The real time length of the data unit in the compression of audio data does not match the frame length of video data. For example, in MPEG (Moving Picture Coding Experts Group/Moving Picture Experts Group), for the video data, in a 29.97 Hz system, the number of time stamps (TS) of one frame is 3003, whereas for audio data, in an 48 kHz MPEG2 Audio Layer II, the number of TSs of one frame is 2160.
For example, in a data stream, such as MPEG, for which video and audio are handled at the same time, when data streams are connected, since connection is performed by using the video data as a reference, at the connection point, continuity of the audio data is lost for compressed audio data having a period different from that of the video data.
Since audio data with lost continuity causes, for example, a failure of a decoding buffer to occur, there is a possibility that decoding cannot be performed correctly in a decoding device. For example, in a case where, in order to maintain the continuity of audio data, the phase lag between a video signal and an audio signal is admitted and the audio signal is directly made continuous, unnatural playback data, such as, for example, the audio data being played back prior to the video data, might result.
Furthermore, depending on the video data to be connected, there are cases in which, in order to prevent the failure of a decoding buffer, a still image whose coding rate is close to zero is inserted at a connection point, so that the processing of the decoding buffer is in time. In such a case, unless audio corresponding to the still image to be inserted is provided, a soundless state occurs in the connection point, and unnatural playback data results.